For use in the high-temperature range, for example in the case of gas turbines, use is often made of nickel-based superalloys. To further increase the strength, use is made of single crystals or components having columnar grains.
What matters in the case of the components having the columnar grains is the grain boundary strength and the grain boundary precipitations or the presence of foreign elements (impurities) which deposit at the grain boundaries. These elements can have a considerable influence on the mechanical properties at the high temperatures.
WO 00/44949 discloses a nickel-based superalloy having a high molybdenum content.
U.S. Pat. No. 6,231,692 likewise discloses a nickel-based alloy having a high molybdenum content.
EP 1 329 527 B1 discloses a nickel-based superalloy in the case of which the elements zirconium and hafnium are added deliberately.
EP 0 855 449 B1 likewise discloses a minimal addition of zirconium.
However, these alloys have a low grain boundary strength and as a result have a negative effect on the overall strength of a component, or are insufficiently ductile owing to zirconium and hafnium.
Relatively small additions of certain elements can have negative effects on these properties of the alloy if they are exceeded.
However, it is highly complex to reduce the contents of such elements. A balance must therefore be found between costs and optimization of the properties of the alloy.